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Topic: Why did Canon make EF-S lenses (Read 12194 times)

Heidrun

It`s stupid that they make lenses that doesent fit on a 1D serie. I want a 10-20 zoom. But it is only for 1,6 crop kamera. Canon is here forcing me to use a Sigma lens like 12-24 instead of providing a quality wide zoom to use on a 1D camera

It`s stupid that they make lenses that doesent fit on a 1D serie. I want a 10-20 zoom. But it is only for 1,6 crop kamera. Canon is here forcing me to use a Sigma lens like 12-24 instead of providing a quality wide zoom to use on a 1D camera

Think about how many APS-C cameras Canon sells, compared to the number of APS-H bodies they sell. I'd argue that they'd be stupid to design a lens mount and series of lenses specific for APS-H - no profit in that. FWIW, you can mount a Tokina 11-16mm on your 1D body, you'll get vignetting a the wide end but it works, and doesn't require any physical modifications to the lens (unlike mounting the Canon 10-22mm on a 1D body).

A 10-20mm non-distorting lens for a FF sensor would be technically very difficult, and would be very exotic and expensive (look at the price of the Nikkor 14-24mm and add a bit more for the even more over-the-top design).

And to answer your more general question posed in the title of your post:Smaller image circle == smaller elements == smaller & lighter lens == cheaper lenses == higher margins & more sales == profit(these are just some of the reasons Canon makes EF-S lenses)

The question you would like to pose is: why Canon doesn't make a set of lenses for the APS-H format. I'll let the rumors of the APS-H format discontinuation, and the sales numbers of APS-H cameras answer that question for me (especially in relation to all APS-C and FF cameras). (And no, I'm not saying the 1D-line of cameras are bad)

FWIW, you can mount a Tokina 11-16mm on your 1D body, you'll get vignetting a the wide end but it works

Really? I did not know that. Very interesting, especially since Canon is discounting refurbished 1D's for $1,500 off the price of a new body ($3,999 vs. $5,499). Out of stock currently, but they have had them in stock within the past month.

Now, if I just had $3,999 to spend on a camera...hmm...camera or college tuition for my daughters? I guess I'll have to stick with the 7D for awhile longer.

Mainly because FF camera's already have the 10-22mm equivalent focal length. It's called the 16-35mmL f2.8.

The 10-22mm covers the same field of view on a crop body as the 16-35mm does on a FF body.

+1and if you don't understand why, how did you afford a 1d?

If you want a 10-22mm native fullframe mount, good luck designing it. it would be massive (to have any decent image quality), and would probably have to use some kind of DO or CaF element, expensive...

Sigma make a 12-24 for full frame, mount 12mm on your 1D and you get the same framing as a 15.6mm on a fullframe.they also make an 8-16 for apsc, same framing as 12-26mm on full frame.

but hypothetically, if you do mount the efs 10-22 on a fullframe, you get a 100*121 degree (h*w) field of view. the sigma 12-24 gives 90*112 degree field of view and a lot less vignetting.

The main problem here is a bad DSLR body choice. 1D is made for professional telephoto stuff (like sports, wildlife, paparazzi... not UWA) while providing faster burst speed (less megapixels) and more reach (1.3 crop) than 1Ds.

Newer lenses use internal zooming so they have to FAKE the focal distance - which is why you see a lens that is easily 200mm long having a 17mm (equivalent) size as the 17 - 85 does - the lens can not get near to 17mm so it has to FAKE this and the easiest way involves moving the rear elements closer than 42mm, if you limit yourself to cheaper cameras with smaller, cheaper sensors you can do this

Only if you need to shoot motion studies in an ultra wide composition and the 7D lacks the framerate or low light noise characteristics required.Every camera is a trade of, and the intended customer group knows quite well that they have to resort to stitching or an additional body if they need ultrawides. OTOH they know how often they will need such wide FOVs - its not exactly part of the job description of the 1D. And if you need to get wide often there is the 5D2 - it doesn't cost much more then a good low volume lens but gives all the other lenses a second field of application and you some additional flexibility and redundancy.

Newer lenses use internal zooming so they have to FAKE the focal distance - which is why you see a lens that is easily 200mm long having a 17mm (equivalent) size as the 17 - 85 does - the lens can not get near to 17mm so it has to FAKE this and the easiest way involves moving the rear elements closer than 42mm, if you limit yourself to cheaper cameras with smaller, cheaper sensors you can do this

He is correct in that the EF-S mount was designed with the ability to move the rear element of the lens closer to the sensor thanks to the reduced mirror size (the reason that EF-S lenses cannot be mounted on FF cameras - they will impede the movement of the mirror during exposure unless you mirror-up before mounting). Third party lenses (as far as I know) do not design lenses to take advantage of the extra distance provided by the alternate mount design. Nikon, OTOH, kept the mount identical and does not produce lenses that protrude further into the body than the original F design (therefore 'DX' lenses can be mounted on FF bodies with no trouble, but will strongly vignette due to the smaller image circle produced by that series of lenses).

So many people just don't get this - which is the main concept here. A full frame lens (the EF) like the FD lenses before it were designed to focus with a (Canon) 42mm distance to focal plane - some other manufacturers used 44mm, 44.5, etc. This put the minimum distance to the mirror at 42mm

I think most people get this. The 'S' in EF-S indicates short back focus. Of course, moving the rear element closer to the imaging plane is not really the main concept at all. The main concept behind an EF-S lens is the smaller image circle, designed to cover an APS-C sensor vs. a FF sensor. As pointed out above, other manufacturers of lenses designed to cover only an APS-C image circle do not shorten the back focus on their mounts, and still, those lenses are smaller, cheaper, and easier to design. The short back focus does make some elements of lens design easier (and ensures that EF-S lenses cannot be used on FF bodies, which I'm sure the marketing department appreciates - and maybe even suggested), but the main concept is the smaller image circle.

Newer lenses use internal zooming so they have to FAKE the focal distance - which is why you see a lens that is easily 200mm long having a 17mm (equivalent) size as the 17 - 85 does - the lens can not get near to 17mm so it has to FAKE this and the easiest way involves moving the rear elements closer than 42mm, if you limit yourself to cheaper cameras with smaller, cheaper sensors you can do this

The 17-85mm lens does not use internal zooming - that lens, like most zoom lenses, extends when you zoom (look at a 70-200mm L zoom for an example of internal zooming).

Your statement that a 17mm lens 'can not get near to 17mm' so the design 'involves moving the rear elements closer than 42mm' is completely incorrect. The focal length of a lens is measured from the imaging plane (i.e. sensor) to the rear nodal point (which is an optical feature of the lens, not a specific element). The nodal point is not the rear element. There's nothing 'fake' about it, or if you prefer to think of it that way, many lenses fake the focal length. The point is that a lens design determines the position of the nodal point, and in some designs (e.g. retrofocus wide angle and long telephoto lenses), that nodal point is positioned outside of the physical space occupied by the lens.

â€¢ If the lens is not intended to be used on "full-frame 35-mm size" sensor cameras, but rather those with a smaller sensor size, it can have a smaller image circle, and this makes it easier to design for a certain set of optical properties with a certain optical performance.

â€¢ If the lens is not intended to be used "full-frame 35-mm size" sensor cameras, but rather those with a smaller sensor size (and thus a smaller reflex mirror, assuming an SLR arrangement), then the lens can have a smaller "back focus" (the physical distance from the rearmost point on the lens to the focal plane), which simplifies the design of lenses with smaller focal lengths.

Overall, then, we might expect that the objective is to allow the design of lenses for use only on "smaller-format" cameras that are less costly, smaller, and/or lighter, for given optical properties and optical performance, than if they were designed to be used on all cameras of the genre, including those with a full-frame 35-mm sensor size.

Note that the focal length quoted for EF-S lenses is (nominally) the "actual" focal length of the lens (the only focal length it has). It is an optical property of the lens, and does not presuppose its use in any particular format size camera . The lens has that property on any camera it will fit, or when in its carton.

The stating of the "full-frame 35-mm equivalent focal length" for a lens as it will be used on a camera of some particular format size, other than "full-frame 35-mm", is intended to allow the real property of interest, the field of view of the lens when used on that camera, to be expressed in a familiar, traditional form which can be compared to work with a full-frame 35-mm format camera. It is not an actual focal length of the lens under any circumstances.

It`s stupid that they make lenses that doesent fit on a 1D serie. I want a 10-20 zoom. But it is only for 1,6 crop kamera. Canon is here forcing me to use a Sigma lens like 12-24 instead of providing a quality wide zoom to use on a 1D camera

Well, I think there are technical reasons and marketing reasons. They needed something to sell to their crop sensor customers that provides the wide angle that is lost due the sensor size. And they needed it on the cheap. From a marketing standpoint it comes in handy that those cheap(er) but relatively good lenses don't fit the full frame bodies, because they want you to buy the very good and expensive specialty lenses in the EF lineup.

And my guess is that in order to prevent people from buying third-party lenses they introduced kind of the mid range lenses that are optically pretty good but slower like the 17-40L.

And for everything wider than 16 or 17 they have a wide variety of primes primes and now even the new 8-15. I mean, seriously, there are maybe a few things that I would like Canon to do differently, but it's really not fair to complain about their lens line up. There is something for every purpose and budget - and still at a better price point than what the other company has to offer, while the quality is traditionally as good or better.

The main reason to make EF-S lens is to take the advantage of the smaller mirror in the APS-C sensor body(The rear lens element can get into the camera body deeper) and smaller image circle. These will make the design of wide angle lnes (or zoom) easier. As for pricing, that is another story. Canon can sacrifice quality to make it cheap (as in the kit lenses)or make it good and expensive (17-55 f2.. I personally think taht Cnnon is smart to make the EF-S lens, especially the 10-22 and the 17-55 f2.8.